1. Field of the Invention
The present invention generally relates to an intersection information supply system supplying information about whether a vehicle is going to pass through an intersection, and more particularly to an intersection information supply system supplying information about whether a vehicle running on a preferred road is going to pass through an intersection at which the preferred road and a non-preferred road intersect, to a vehicle running on the non-preferred road. In addition, the present invention relates to an onboard information transmission apparatus applicable to the above intersection information supply system.
2. Description of the Related Art
Conventionally, such an intersection information supply system is disclosed, for example, as an encounter collision avoidance display apparatus, in Japanese Laid-Open Patent Application No.5-28400. In this system, when a vehicle running on a preferred road is detected at a position a predetermined distance before an intersection at which the preferred road and a non-preferred road intersect, a light of a warning display board installed at a position from which a driver of a vehicle approaching the intersection on the non-preferred road can look at the lamp is turned on.
According to such a conventional system, even if buildings causes the visibility at the intersection to be poor, the driver of the vehicle approaching the intersection on the non-preferred road can recognize, based on the turned-on lamp of the warning display board, that a vehicle is approaching the intersection on the preferred road. Thus, the vehicle can more safely enter the preferred road from the non-preferred road.
A detector used to detect vehicles approaching the intersection on the preferred road can not distinguish the vehicles from other moving bodies. Thus, in a case in which bicycles or pedestrians are detected by the detector, the lamp of the warning display board is turned on. The detector detects the presence of moving bodies. Thus, if a body moving away from the intersection is in a detecting area of the detector, the detector detects the body. In this case, based on the detecting result, the lamp of the warning display board is turned on.
As has been described above, the conventional intersection information supply system does not necessarily supply useful information to the driver of the vehicle approaching the intersection on the non-preferred road.